未知题型 下面是类MyClass的定义，对定义中各种语句描述正确的是( )。class MyClass { publiC： void MyClass(int a) //①{ x=a； ) int func(int a，int b) //②{ x=a； y=b； } int func(int a，int b，int c=0) //③{ x=a； y=b； z=c； } static void resetValue() //④{ x=0； } private： int X，y，Z； }；

未知题型 随着计算机应用范围的扩大，如何确保计算机的安全性显得日益重要。在常用的对文件进行安全性管理的措施中，(18)的主要任务是不允许未经核准的用户进入系统；(19)是通过系统管理员或文件主对文件属性的设置，来控制用户对文件访问。

未知题型 In the following essay, each blank has four choices. Choose the best answer and write down on the answer sheet.In low - speed network, it is usually adequate to wait for congestion to occur and then react to it by telling the source of packets to slow down. In high - speed networks, this approach often works poorly, because in the(66)between sending the notification and notification arriving at the source, thousands of additional(67)may arrive. In ATM network, a major tool for preventing(68)is(69)control. When a host wants a new virtual(70), it must describe the traffic to be offered and the service expected.